KEF LS50 Wireless Internal vs External DAC ??

I am finding my KEF LS50 Wireless to sound warmer, fuller, and more spacious, with better resolution of image location, when running my streamer (Audio Alchemy DMP-1/PS-5 power supply) to Audio Alchemy DDP-1 DAC/Preamp into its RCA inputs (which are then internally converted via ADC and again DAC) than I am running my streamer direct to the speakers via USB.
Given the numerous redundant conversions at play, I speculate that the ADC conversion is so much more transparent than I imagined and that the internal DAC in the KEFs is so much worse than I expected that I would recommend others use a high-quality external DAC with these speakers (even if they are to be internally re-DACed within them). 
Anyone have this experience?? Thoughts??
Hello, I'm a KEF LS50W user from Taiwan.
I have the same feeling as you.
When i connected Mytek 192 on KEF LS50W , it obviously sounds better than the internal dac.
It is really weird but quite a funny thing!
quite happy to find someone got the same feeling.

One word - jitter. Most of the benefit of a good modern DAC will be the high quality asynchronous clock and jitter rejection. Perhaps the DAC in the LS50 is not as capable as an outboard DAC - however performing A to D and then D to A on the same board within the LS50 might not be as jittery given it is all happening on the same circuit board.
Hi-Fi News apparently found the same to be true, using the Chord 2QuteHD as an external DAC. It seems there is now consensus on this issue.
With Hugo as an external DAC and run RCA into KEF LS50 wireless, it sounds more spacious and detailed.
However, there is a big problem which made me come back to use USB rather than RCA port.
When I use Hugo, the vocal is apparently not as clear as internal DAC, this is a huge difference, you need not AB test to tell the difference.
I think buy some USB isolation gear EX:Schiit wyrd and Singxer UIP-1 is the best way to make LS 50 wireless Hifiest
With an external DAC you can upgrade.  I’m happy with my LS50s ands Auralic Vega DAC since I have a lot of DSD files and the LS50 wireless can’t play them.
hello, i've used the ELAC Discovery music server connected to the KEF LS50 W and i can confirm that the RCA connection nets the best sound.
Noticeably better than when using the KEF's DAC via the Optical connection.

I can only assume that the LS50 W DAC is not comparable to outboard DACs and dedicated music servers.